The speed of operation of integrated circuits is limited by signal delay in long interconnect lines. As memories incorporate more memory cells, the decoding circuits become more complex increasing the length of lines through which signals must pass, and the column length increases slowing down signal propagation. Improvement in the speed of operation of memory circuits is desirable because applications demand higher speeds. Higher speeds correspond to shortening the access time of memories. Access time is the elapsed time from when an address is presented to a memory until data stored at that address is available at the memory output.
Speed improvements are possible when using current-mode signal transporting techniques as opposed to voltage-mode signal transporting techniques. A sense amplifier is used in a semiconductor memory to detect and amplify a small signal on a column or bit line, and forward the amplified signal to the output of the sense amplifier. Current-mode sense amplifiers, such as the current mode sense amplifier is disclosed in FIG. 5(a) of Current-mode Techniques for High-speed VLSI Circuits with Application to Current Sense Amplifier for CMOS SRAM's, IEEE Journal of Solid-States Circuits, vol.26, no. 4, April 1991, pp. 525-535, are subject to potential problems. Junction leakage, or a temporary power supply overvoltage, sometimes referred to as a bobble, cause a current-mode sense amplifier to require prolonged access time.